This application is based on application No.11-340116 filed in Japan on Nov. 30, 1999, the content of which incorporated hereinto by reference.
This invention relates to a method of manufacturing a photovoltaic device.
A prior art method of manufacturing a photovoltaic device is disclosed In Japanese Non-examined Patent Publication No.10-107305 issued on Apr. 24, 1998. This method of manufacture forms a first electrode film, a light-active semiconductor film, and a transparent conducting film over the whole surface of an insulating substrate. Subsequently, by scanning a spot laser beam to form dividing grooves, layered structures corresponding to a plurality of power generating regions are formed.
In prior-art photovoltaic devices described above, a top surface protective film is necessary to further improve reliability. However, the laser-formed dividing grooves for dividing the power generating regions are approximately 50 xcexcm to 100 xcexcm wide. When the devices having the above protective film are used for long period or subjected to reliability testing, the protective film delaminates In the dividing grooves and moisture intrusion can occur.
The present Invention was developed to solve these types of problems, It is thus an object of the present invention to provide a method of manufacturing a photovoltaic device which Is easy to manufacture and delivers good reliability.
The above and further objects and features of the invention will more fully be apparent from the following detailed description with accompanying drawings.
The present invention is a method of manufacturing a photovoltaic device which forms a first electrode layer, a light-active semiconductor layer, and a transparent conducting layer in power generating regions on a substrate having an insulating top surface.
The method of manufacture of the present invention comprises the following steps; forming said first electrode layer and said light-active semiconductor layer on the insulating surface; forming a transparent conducting film over most of the insulating surface including the region of the light-active semiconductor layer, said transparent conducting film constituting said transparent conducting layer; forming a patterned transparent protective layer being passed by visible light but not passed by ultraviolet light, as masking material on said transparent conducting film over said power generating regions; and forming said transparent conducting layer by removing portions of said transparent conducting film not masked by the patterned transparent protective layer by irradiating ultraviolet laser light over most of the substrate,whereby after the above steps, said patterned transparent protective layer is left.
In the method of manufacture of the present invention, protective material can be disposed in the portions of the transparent conducting film removal for additional protection. Further, the method of manufacture of the present invention uses polyethylene terephthalate resin as the transparent protective layer.
In the method of manufacture described above, protective layer, which is selectively passed by visible light but not passed by ultraviolet light, masks the transparent conducting film. The transparent conducting layer is patterned and formed by removing portions of the transparent conducting film not masked by the patterned transparent protective layer by irradiating ultraviolet laser light over most of the substrate. The transparent protective layer is not removed after irradiation of ultraviolet laser light because it serves as a protective film covering the transparent conducting layer. Specifically, the transparent protective layer, which protects the device, is used as masking material for partial removal of the transparent conducting film. A photovoltaic device manufactured by this method Is protected by the transparent protective layer and has Improved reliability.
In a method which further protects the device by disposing protective material in the portions of the transparent conducting film removal, the protective material can achieve sufficient adhesion to the light-active semiconductor layer over a wide area. This is because the width of the regions where the transparent conducting film is removed by the reason of not masked by protective layer can be made wider than the prior-art technology dividing grooves (50 xcexcm to 100 xcexcm) created by spot laser beam. Consequently, protective material delamination and moisture ingress in these regions can be reduced over long duration use or reliability testing for a photovoltaic device manufactured by this method.